Programming Entity Framework

Chapter 3. Querying Entity Data Models

You can query Entity Data Models in a variety of ways. Some ways you will choose for personal preference and others you will choose so that you can leverage particular benefits.

In this chapter, you will finally get to write some code and retrieve some data by writing queries using the two query syntaxes that the Entity Framework provides: LINQ to Entities and Entity SQL. In addition, you will learn about query syntax versus method-based syntax, including the Entity Framework’s query builder methods. By the end of the chapter, you will have gained a high-level understanding of all of the query options and their basic uses. In further chapters, you will write more complex queries; the foundation you will receive from this chapter will make that task much easier.

In addition, at the end of this chapter you’ll find an extremely important section on query execution. Understanding the possibility of inadvertently executing a query in your Entity Framework applications can help you to avoid performance problems caused by your application unknowingly and unnecessarily making calls to the database.

Query the Model, Not the Database

Here is where you will experience the difference between writing queries against a data model rather than the database. In this chapter, you will learn how to construct queries against the EDM that you created in Chapter 2, and you will learn to let the Entity Framework take it from there. The Entity Framework will process your ...